Coal conversion process

ABSTRACT

1. A PROCESS FOR THE PREPARATION OF LIQUID PRODUCTS FROM COAL WHICH COMPRISES: (A) PREPARING A SLURRY OF FINELY DIVIDED COAL PARTICLES IN A HYDROGENATED AROMATIC HYDROGEN-DONOR SOLVENT HAVING A BOILING POINT IN THE RANGE BETWEEN ABOUT 350*F. AND ABOUT 800*F. IN A SLURRY PREPARATION ZONE; (B) INTRODUCING SAID SLURRY FROM SAID SLURRY PREPARATION ZONE INTO A FLUIDIZED BED COKING UNIT REACTION ZONE; (C) WITHDRAWING OVERHEAD PRODUCTS FROM SAID FLUIDIZED BED COKING UNIT REACTION ZONE AND RECOVERING AN INTERMEDIATE FRACTION BOILING IN THE RANGE BETWEEN ABOUT 350*F. AND ABOUT 800*F. (D) HYDROGENATING SAID INTERMEDIATE FRACTION AND INTRODUCING AT LEAST PART OF THE HYDROGENATED PRODUCT INTO SAID SLURRY PREPARATION ZONE; (E) TRANSFERRING SOLIDS FROM SAID FLUIDIZED BED COKING UNIT TO A BURNER AND BURNING A PORTION OF THE SOLIDS TO PROVIDE HEAT FOR THE PROCESSL AND (F) RECYCLING HOT SOLIDS FROM SAID BURNER TO SAID FLUIDIZED BED COKING UNIT REACTION ZONE.

- S. J- COHEN` TAL COAL CONVERSION PROCESS Ost. 15. 1974 United StatesPatent O 3,841,991 COAL CONVERSION PROCESS Saul J. Cohen, Chester, NJ.,and Jack M. Hoehman, Cobham, England, assignors to Esso Research andEngineering Company Filed Apr. 5, 1973, Ser. No. 348,397 Int. Cl. Cg1/04 U.S. Cl. 208-8 10 Claims ABSTRACT OF THE DISCLOSURE A process forthe preparation of liquid products from coal wherein nely-divided coalparticles are slurried in a hydrogen-rich liquid hydrocarbon solvent atlow temperature and substantially atmospheric pressure and the resultingslurry is passed into a fluid bed coking unit Where conversion of thecoal, solids separation, and thermal cracking of a heavy product takeplace simultaneously. An intermediate fraction taken overhead from thecoking unit is hydrogenated and a portion of the product is recycled foruse as coal solvent. The remaining overhead streams are sent toconventional downstream refining units and solids derived from the coalare withdrawn as char.

BACKGROUND OF THE INVENTION (1) Field of the Invention This inventionrelates to the manufacture of liquid hydrocarbons from coal and isparticularly concerned With an improved coal conversion process whereinconversion of coal, separation of solvent, and thermal cracking of heavyproducts are carried out simultaneously in a fluidized coking unit.

(2) Description of the Prior Art There is substantial interest in thedevelopment of processes for the manufacture of synthetic crude oils andliquid hydrocarbons from coal. Among the more promising processes ofthis type are those based upon the solvent extraction of liquidconstituents from the coal with an aromatic solvent. Such processesrequire that the coal be digested at elevated temperature and pressurewith a hydrogen-donor solvent, generally in the presence of addedhydrogen gas. The hydrogen contributed by the solvent and gas increasesthe amount of extract recovered and upgrades the liquid products.Following this solvent treatment, the products are separated to yield ahigh boiling extract containing liquid hydrocarbons derived from thecoal and a solid phase composed of insoluble coal residues. The extractis then subjected to catalytic cracking or other rening processes forconversion of the high boiling material into lower boiling hydrocarbons.The solids separated from the extract are generally subjected to a lowtemperature carbonization treatment for the production of additionalliquid products and char useful as fuel. Although processes of this typehave advantages over some of the other coal conversion methods suggestedin the past, they generally require a large plant investment and areexpensive to operate. Efforts to improve the economics of such processeshave to date been only partially successful.

SUMMARY OF THE INVENTION This invention provides an improved process forthe manufacture of liquid hydrocarbons from coal which at least in partovercomes the disadvantages of earlier processes and permits conversionof the coal at relatively low cost. The improved process of theinvention involves the rice preparation at low temperature andsubstantially atmospheric pressure of a slurry of finely-divided coalparticles in a hydrogenated aromatic solvent derived from coal and thesubsequent introduction of this slurry into a fluidized bed coking unitoperating at a temperature in the range between about 900 and about 1l00F. Liquefaction and hydrogenation of the coal, separation of the solids,and thermal cracking of the heavy liquid products take place in thecoking unit in the presence of the hydrogen-rich solvent, increasing theyield of low boiling liquid products and decreasing the yield of char.The products taken overhead from the coking unit reaction zone arefractionated and an intermediate liquid stream boiling within the rangeof about 400 -F. and about 700 F. is passed to a catalytic hydrogenationunit. A portion of the resulting hydrogenated aromatic solvent producedin the hydrogenation zone is recycled for use in preparing thecoalsolvent slurry. The remaining liquid products obtained byfractionation of the overhead stream from the coking unit reaction zoneare sent to conventional downstream refining units for furtherprocessing. Solids produced in the coking unit reactor are transferredto a burner where a portion of the hydrocarbon solids are burned togenerate heat for the process. A portion of the unburned solids arerecycled to the reaction zone and the rest are withdrawn as productchar.

The process of the invention has numerous advantages over conventionalcoal liquefaction processes in that coal conversion, solids separation,and thermal cracking of heavy liquids produced from the coal all takeplace within the coking unit reactor and hence separable liquefaction,solids separation and coking or carbonization units are not required.This permits savings in plant investment and operating costs. It alsoresults in much better heat integration than can be obtained inconventional processes, permits generation of all of the process heatfrom coal without the use of complex coal-red furnaces, eliminates theneed for slurry-handling heat exchangers and other equipment whichnormally poses severe design, operation and maintenance problems inconventional processes, obviates the necessity for handling slurries atthe high pressures required in prior art processes, and permitssignificant reductions in pumping and compression costs. Moreover, ithas been found that the yields obtained in the process of the inventioncompare favorably with those obtained in other coal conversion processeswhich require extraction of the coal with an aromatic solvent and thatthe molecular hydrogen which is generally needed to provide reasonableconversion levels in the liquefaction zone of conventional processes isnot necessary. These and other advantages, coupled with the savings inplant investment and operating costs, make the economics of the processappear attractive.

BRIEF DESCRIPTION OF THE DRAWING The single figure in the drawing is a.schematic flow sheet of a preferred embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the process depicted in thedrawing, raw coal from a coal preparation plant or storage is introducedinto the system through line 10 and fed through hopper 11 and a screwconveyor or similar device 12 into a slurry preparation vessel 13. Thecoal introduced will generally be in a finely-divided state and willnormally consist of particles between about 1A inch and about 325 meshon the U.S. Sieve Series Scale in size. 'The use 0f particles of about 8mesh or smaller is generally preferred. The coal may be bituminous,sub-bituminous or lignite. Special drying and other coal pretreatmentsteps are not normally necessary but may be used if desired. A typicalinspection vof a coal suitable for purposes of the invention is asfollows:

TABLE I Typical Coal Inspections Wt. percent Moisture, saturated 13.0Ash, dry 10.6 Mineral matter, dry 12.8 Volatile matter, DMF 1 45.1 Fixedcarbon, DMF 54.9 Carbon, DMF 79.1 Hydrogen, DMF 5.6 Oxygen, DMF 10.6

Nitrogen, DMF 1.2 Sulfur, total, dry 4.7 Sulfur, pyritic, dry 1.7Sulfur, organic, DMF 3.4 B.t.u./lb., dry 12,610 B.t.u./lb., DMF 14.360

1 Dry, mineral-free.

An aromatic hydrogen-donor solvent is introduced into slurry preparationvessel 13 through line 14 simultaneously with the coal. The solventemployed will normally be a coal-derived liquid produced by thehydrogenation of an intermediate overhead stream boiling between 350 F.and about 800 F., preferably between about 400 F. and about 700 F. Thisstream is made up predominantly of hydrogenated aromatics, naphthenichydrocarbons, phenolic materiais, and similar compounds and willnormally contain at least 30 percent by weight, preferably at least 50percent by weight, of compounds which are known to be hydrogen donorsunder the temperature and pressure conditions employed in the uidizedcoking reaction zone. Other hydrogen-rich solvents may be used in lieuof or in addition to such a coal-derived liquid, particularly on initialstart-up of the process. Suitable aromatic hydrogen-donor solventsinclude hydrogenated creosote oil, hydrogenated intermediate productstreams from the catalytic cracking of petroleum feedstocks, and othercoal-derived liquids which are rich in indane, C to C12 Tetralin,Decalin, biphenyl, methylnaphthalene, dimethylnaphthalene, C12 and C13acenaphthenes, di, tetraand octahydroanthracene, tetrahydroacenaphtheneand similar donor compounds.

A typical hydrogenated, coal-derived liquid boiling between about 350"F. and about 800 F. which is rich in hydrogen-donor compounds and istherefore suitable for use as an aromatic hydrogen-donor solvent in theprocess of the invention is described in Table 1I below.

TABLE II.-TYPICAL HYDROGEN-DONOR SOLVENT A. Distillation Cumulative wt.Sp. gr., percent over- Tenp., F. at 760 mm.:

Total B. Mass speetro analysis Element analysis, nngs wt. percentTypical compound CnHz n n alkylbenzene C Han-s tetralin C Harm indeneCnH2n12 naphthalene l .sulfur Total CnHzn-M acenaphthene CHzn-ieacenaphthylcne C Hh-i5 phenanthrene CnHrn-ze cholanthrenes OUH; -25benzopyrenes co @com It will be understood, of course, that thecomposition of the recycle solvent obtained by the hydrogenation of anintermediate fraction of the coal-derived liquids will depend in partupon the particular coal employed, the coking conditions used, thestart-up solvent selected, the boiling range of the intermediatefraction selected, the hydrogenation conditions employed, and thelikeand that the composition of the recycle stream may therefore differsomewhat from that set forth above.

The coal introduced into the slurry preparation vessel 13 by means ofconveyor 12 and the hydrogen-rich solvent introduced through line 14 arecombined in the preparation vessel in a ratio of from about 0.5 to about5 parts of solvent per part of coal by weight. The ratio selected for aparticular preparation will depend in part on the particle size of thecoal introduced into the process, the moisture content of the coal, thetemperature and the viscosity of the solvent employed, the degree ofagitation provided by stirrer or similar mixing device 1S, and otherconsiderations. In general it is preferred to employ from about 1.5 toabout 3 parts of solvent per part of coal by weight. The slurry willnormally be prepared continuously as indicated in the drawing. In somecases, however, a batch slurry preparation technique may be used.

The slurry prepared in vessel 13 is discharged from the vessel throughline 16. The slurry temperature will depend primarily upon thetemperature of the solvent introduced through line 14 and thesolvent-to-coal ratio. In general, the slurry temperature will rangebetween ambient and about 200 F. Little or no reaction takes placebetween the coal and solvent in the preparation vessel and hence thetemperature and residence time in vessel 13 are not critical.

The solvent-coal slurry prepared as described above is mixed with a highboiling bottoms stream introduced through line 17 and passed from line16 into injection lines 18, 19 and 20. From here the feed slurry isinjected into the reactor Vessel 21 of a fluidized coking unit ofconventional design. Reactor vessel 21 contains a bed of coal and charparticles which is maintained in a uidid state by means of saturatedstream introduced near the bottom of the vessel through line 22. The bedtemperature is maintained between about 900 F. and about 1100" F. bymeans of hot char which is introduced into the upper part of the reactorvessel through riser 23. The pressure -within the reactor will normallyrange between about 10 and about 30 pounds per square inch guage.

The coal-solvent slurry introduced into reactor 21 is sprayed onto thesurfaces of the downwardly moving char particles in the uidized bed andrapidly heated to bed temperatures. Hydrocarbons present in the coal arehydrogenated and liquefied in the presence of the hot solvent. As thetemperature increases, the coal-derived liquids and solvent arevaporized and heavier constituents undergo thermal cracking reactions.The vaporized products, steam, and entrained liquids move upwardlythrough the bed, pass through cyclone separator 24 where char particlespresent in the uid stream are rejected, and move into scrubber 25. Thechar particles and unreacted coal residue and other solids movedownwardly in the uidized bed and are withdrawn from the bottom ofreactor 21 to standpipe 26 containing slide valve 27.

The uid stream passing overhead from reactor 21 into fractionator 25 iscooled to condense out a heavy bottoms fraction boiling in excess ofabout 1000 F. and scrubbed to remove the remaining solids. The heavybottoms product containing the solids recovered in the fractionationoperation is recycled through line 17 for reintroduction into thereactor with the slurry of coal and solvent. In the upper part of thefractionator tower, the lighter constituents are fractionated. A heavygas oil boiling up to about 1000 F. is withdrawn through line 28 andsent to downstream rening units not shown in the drawing for furtherprocessing. An intermediate stream boiling in the range between about350 F. and about 800 F., preferably between about 400 F. and about 700F., is withdrawn through line 29 and a portion of this stream is cooledin heat exchanger 30 and recycled to the upper part of the tower. Therest of the intermediate stream is passed to a catalytic hydrogenationzone 31. Lighter constituents are taken overhead from the scrubberthrough line 32 to a condenser 33 from which naphtha is recoveredthrough line 34 and noncondensable gases are taken olf through line 35.'Ihe naphtha and gas streams may be further processed in theconventional manner.

The char withdrawn from the bottom of reactor 21 through standpipe 26and slide valve 27 passes into riser 36 where steam is added throughline 37 to aid in moving the solids. The slide valve serves to controlthe bed level in reactor 21 so that the depth of the bed will normallyrange between about 30 and about 50 feet. 'I'he bed velocity generallyranges from about l to about 3 feed per second. The reactor holding timeis preferably between about and about 30 seconds.

The char particles in riser 36 are carried upwardly into burner 38. Airis introduced into the bottom of the burner through line 39 to aid inmaintaining the char particles in the uidized state and support thecombustion of a part of the char. The burner temperature is maintainedin the range between about 1100 F. and about 1200 F. by regulating theamount of air admitted. The pressure in the burner vessel will normallybe similar to that in the reactor, between about 10 and about 30 poundsper square inch guage. Hot char particles are withdrawn from the burnerby means of standpipe 40 containing slide valve 41 and recycled withsteam added at line 42 through riser 23 to the reactor 21. The largerchar particles are taken olf through line 43 containing slide valve 44and passed to quenching zone 45 where water is added by means of line 46to cool the char. Fine solids present in the char product are carriedoverhead with the steam formed in the quenching vessel and are recycledto the burner through line 47. The cooled char product is withdrawn fromthe bottom of the quenching vessel through line 48 containing slidevalve 49 and sent to storage for use as a high grade fuel or thegeneration of synthesis gas to be used in the manufacture of hydrogen.Air may be added through line 50 to assist in handling the char product.The combustion gases formed in the burner are taken over head, passedthrough cyclone separators 5l and 52, and discharged as stack gasesthrough valve 53 and line 54. The bed velocity in the burner willnormally range between about 2 and about 3 feet per second and the depthof the bed is generally controlled at between about l0 and about feet.

The intermediate boiling fractiontaken overhead from the coking unitscrubber and passed to hydrogenation zone 30 as described earlier isheated to the hydrogenation temperature of from about 500 F. to about1000 F. in furnace 55 before being introduced into the hydrogenationzone. Here the hot fluid is contacted with hydrogen introduced throughline 56 at a pressure between about 200 and about 5000 pounds per squareinch in the presence of a sulfur-resistant hydrogenation catalyst suchas Cobalt molybdate, cobalt molybdate on alumina, nickel tungsten,molybdena on alumina or the like. Hydrogenation temperatures in therange between about 600 and about 750 F. and pressures between about 500and about 3000 pounds per square inch guage are normally preferred.Hydrogen treating levels in the range from about 200 to about 4000standard cubic feet per barrel of feed will normally be used. Thehydrogenated aromatic product is withdrawn from hydrogenation zone 31through line 57 and passed to a condenser and separator 58 from whichgases are taken overhead through line 59 and liquids are removed throughline 60. The gases from the condenser and separator are scrubbed inrecycle scrubber 61 and then recycled through line 62 to the inputhydrogen stream to hydrogenation vessel 31. The bottoms product from thecondenser separator is introduced into stripper 63 where gasescontaining hydrogen sulde, nitrogen compounds and the like are takenoverhead through line 64. The hydrogenated aromatics product from thestripper is withdrawn through line 65. A portion of this product isrecycled through lines 66 and 14 for use as solvent in the slurrypreparation vessel 13. The remaining hydrogenated aromatic material isrecovered and sent to downstream refining units or storage.

The nature and advantages of the process of the invention are furtherillustrated by the results obtained in pilot plant tests carried out ina small scale fluidized coking unit. Sub-bituminous Wyodak coal having amoisture content of approximately 30% was crushed and screened to obtaina mesh product. This material was mixed with a hydrogen-donor solvent toform a slurry containing 2 parts of oil per part of wet coal by weight.The solvent employed was one prepared by the hydrogenation of acoal-derived aromatic oil having a boiling range prior to hydrogenationof from about 400 to about 700 F. This solvent contained 8.68 weightpercent hydrogen, had a hydroaromatic index of 83.3, and had a specilicgravity of 1.0182. The coal-solvent slurry was fed to a uidized cokingunit operated at a reactor temperature of 1000 F. and a pressure of 13pounds per square inch guage. The steam dilution rate was 2l weightpercent, based on the slurry, and the reactor holding time was 14.6seconds. Gases were taken otf overhead from the reaction vessel, liquidswere condensed and collected, and the coke formed was recovered at theend of the run. The products obtained, based on diy coal fed to theprocess, included 20.3 weight percent gases, 20.9 weight percentliquids, 51.0 weight percent char and 7.8 weight percent water. Thecomposition of the gases and the material balance for the run are shownin Table III below.

Following the run referred to above, a second run was made underessentially the same conditions except that a nonhydrogenatedcoal-derived oil having a 400 to 700 F. boiling range was used in lieuof the hydrogendonor solvent employed earlier. This material contained6.57 weight percent hydrogen and had a specic gravity of 1.0616. AFischer assay was also run on a sample of the coal. The results obtainedin the three tests referred to above are set forth in Table III.

TABLE IIL-COKING F WYODAK COAL SLURRIES [Minus 100 mesh coal ofapproximately Ili, mailture-content, 2:1 slurry oil/wet eo Hydrogen-Fischer donor Raw assay solvent 1 oil 2 Wyodak slurry slurry coal Cokingconditions:

Temperature, F 1,000 1, 000 1,010 Pressure, p.s.i.g 13 13 (e) Steamdilution, wt. percent of slurry 5 21. 0 18. 0 N one Reactor holdingtime, seconds 14. 6 15. 3

Yields, wt. percent on dry coal; gas:

Hg 1. 45 0. 61 0. 06 3. 90 2. 50 1. 81 0. 75 0. 33 0. 34 1. 72 0. 81 0.59 0. 72 0. 45 0` 25 0. 59 0. 30 0. 18 0. 03 0. O2 0. 0l 0. 62 0. 42 0.24 0. 32 0. 80 0. 51 1. 50 1. 04 1. 75 8. 40 8. 51 5. 85 0. 21 0. 11 0.1l

20. 9 12. (l 12. (i 51.0 63. 7 64. 5 7. 8 6. 9 l0. 3

Run material balance 100. 0 99. 5 99. 1

Cg- Gas 'eld (includin CO, CO2,

II. 10.3 15.7 11.0 Cri' Liquid Yield 21. 9 5 13. 2 13. 3

1 Coal-derived 40G-700 F. solvent, 8.68 wt. percent hydrogen, 83.3hydroaromatic index, 1.0192 sp. gr.

2 40G-700 F. cut, 6.57 wt.. percent hydrogen, 1.0616 sp. gr.

3 Includes moisture in the coal, expressed as wt. percent on wet slurryfed.

4 Not adjusted to close material balance. Does not include (31+ yield. 5Estimated. Atmospheric.

It can be seen from the above table that the yield of char obtained withthe hydrogen-donor solvent was signicantly lower than that obtained withthe nonhydrogenated oil and that obtained in the Fischer assay. Thislower char yield indicates that a significant quantity of the coal washydrogenated and lique-ed in the coking unit. The liquid yield obtainedwith the hydrogen-donor solvent was more than 160% of the Fischer assayyield and compares favorably with that obtained in conventional coalliquefaction processes. As pointed out earlier, the conventionalprocesses normally require the addition of molecular hydrogen ifacceptable yields are to be obtained and hence the results obtained inaccordance with the invention Without adding hydrogen are surprising. Itshould be noted that the liquid yield in the run carried out with thenonhydrogenated oil was estimated because of a small leak in the cokingreactor during the second run. The values shown in the table appear tobe approximately correct, however, and are supported by ythe Fischerassay values. It will be recognized, of course, that some of the charand gases obtained were contributed by the slurry oils. Based uponresults obtained in coking oils in the absence of coal, it is estimatedthat the char yield on 4coal alone, after backing out the predicted charyield from the oil, was about 55% for the nonhydrogenated oil and about46% for the hydrogenated slurry oil. Similarly, the gas yield from thecoal alone is estimated to have been about 12% for the hydrogenated oiland about 16% for the nonhydrogenatcd oil. These values show that theuidizcd coking of coal in the presence of a hydrogen-donor solvent asdisclosed above has substantial advantages -over conventional coalliquefaction processes and coking processes carried out without such asolvent.

The advantages of the process of the invention are further illustratedby the results of tests in which the product from a low severity coalliquefactlon operation and a slurry of coal in a hydrogen-donor solventwere sepa- Iately Coked in a fluid bed coking uni-t. The coalliquefaction product was obtained by the liquefactlon of an Illinoiscoal in the presence of a heart cut hydrogenatcd creosote oil and addedmolecular hydrogen at a temperature of about 800 F. and a pressure of350 pound-s per square inch gauge. This liquefaction product was ed to asmall scale lluidized bed coking unit oper-ated at a temperature of l000F. and a pressure of 13 pounds per square inch gauge. The steam dilutionrate was 11.4v weight percent based on iced, and the reactor holdingtime was 26.6 seconds. The coking operation resulted in the productionof 2.9 Weight percent gas, 69.0 Weight percent liquids, and 28.1 Weightpercent char. The char yield, based on the coal liquefied, was 48%. TheCokin-g run in which a slurry of coal and solvent was used was carriedout by irst crushing and screening a sample Of the Illinois coal to lessthan 200 mesh. This coal was then added to the same heart cuthydrogenated creosote oil used in the earlier run to produce a slurryhaving a s01- vent-to-coal ratio of 4.5 to l. The coking unit feed pumpand nozzle design precluded the use of a more concentrated slurry.During coking of the slurry, a steam dilution rate somewhat higher thanthat employed in the earlier run was used to avoid plugging of thenozzle in the colring unit and hence the reactor holding time was lowerthan in the earlier run. The char yield on coal was 44.4 weight percent.The results of these two runs are set forth in Table IV below.

TABLE Tf-COKIN G TESTS 1 Liquid yields were adjusted slightly to closematerial balance.

The data set forth in the above table show that the direct coking of aslurry of coal in a hydrogen-donor solvent in accordance with theinvention resulted in a char yield of only 44.4 weight percent based oncoal, compared t0 a yield of about 48% where the coal was rst liqueedand the liquefaction product was recovered and coked. The gas yield inthe process of the invention was only 11.5 Weight percent on coal,compared to a yield of about 8 weight percent in the l'iquefaction stepand about 5 weight percent in the coking of the liqueaction product.Although these differences may in part be due to the shorter reactorholding time employed in the direct coking operation, the resultsdemonstrate that the process of the invention permits relatively highyields of liquid products without the addition of molecular hydrogen andthat these yields compare lfavorably with those obtained in conventionaloperations involving separate liquefaction, solids separation, andcoking steps.

The carrying out of the liquefaction, solids separation, and cokingsteps simultaneously in a iluidized bed coking unit in accordance withthe invention eliminates the investment, operating and maintenance costsrequired if separate liquefaction and solids separation equipment isused; provides much better heat integration and thermal eiciency thancan be obtained in conventional processes; permits generation of all ofthe required process heat from coal Without the usc of complex andexpensive coal-fired furnaces and auxiliary equipment; alleviates theneed for heat exchangers and other equipment for handling hightemperature slurries which normally poses severe design, operating andmaintenance problems in conventional operations; permits signicantreductions in pumping and maintenance costs; and has other advantagesover processes suggested in the past. These engineering and economicadvantages, the favorable yields of liquid products, and the ability tosecure such yields without the addition of molecular hydrogen make theprocess of the invention attractive in a variety of differentapplications.

What is claimed is:

1. A process for the preparation of liquid products from coal whichcomprises:

(a) preparing a slurry of finely divided coal particles in ahydrogenated aromatic hydrogen-donor solvent having a boiling point inthe range between about 350 F. and about 800 F. in a slurry preparationzone;

(b) introducing said slurry from said slurry preparation zone into auidized bed coking unit reaction zone;

(c) withdrawing overhead products from said uidized bed coking unitreaction zone and recovering an intermediate fraction boiling in therange between about 350 F. and about 800 F.;

(d) hydrogenating said intermediate fraction and introducing at leastpart of the hydrogenated product into said slurry preparation zone;

(e) transferring solids from said uidized bed coking unit to a burnerand burning a portion of the solids to provide heat for the process; and

(f) recycling hot solids from said burner to said fluidized bed cokingunit reaction zone.

2. A process as defined by claim 1 wherein said fluidized bed cokingunit reaction zone is maintained at a temperature between about 900 F.and about 1100 F. and at a pressure in the range between about and about30 pounds per square inch gauge.

3. A process as defined by claim 1 wherein said slurry zone at atemperature between ambient and about 200 F.

4. A process as defined by claim 1 wherein said slurry is prepared withfrom about 0.5 to about 5 parts of solvent per part of coal by weight.

5. A process as defined by claim 1 wherein said intermediate fractionlhas a boiling range between about 400 F. and about 700 F.

6. A process as defined by claim 1 wherein said hydrogenated aromatichydrogen-donor solvent contains at least 30 percent by weight ofcompounds known to be hydrogen donors under the temperature and pressureconditions in said fluidized bed coking unit reaction zone.

7. A process as dened by claim 1 wherein said slurry is introduced intosaid uidized bed coking unit reaction zone in the substantial absence ofadded molecular hydrogen.

8. A process as defined by claim 1 wherein said intermediate fraction ishydrogenated at a temperature in the range between about 500 F. andabout 1000 F. and at a pressure in the range between about 200 and about5000 pounds per square inch in the presence of a sulfurresistanthydrogenation catalyst.

9. A process as dened by claim 1 wherein said coal particles have aparticle size between about 1A inch and about 325 mesh on the U.S. SieveSeries Scale.

10. A process as defined by claim 1 wherein said coal is asubdbituminous coal.

References Cited UNITED STATES PATENTS 2,624,696 11/ 1953 Schutte208-165 2,982,701 5/1961 Scott 20S-l1 3,505,201 4/ 1970 Hodgson et al.208-8 3,523,886 8/1970 Gorin et al 208-8 3,565,766 2,/1971 Eddinger etal. 201-23 3,617,513 '1l/1971 Wilson 208-8 3,503,864 '3/ 1970 Nelson208-10 VERONICA OKEEFE, Primary Examiner U.S. Cl. X.R. 201-23; 208-10

1. A PROCESS FOR THE PREPARATION OF LIQUID PRODUCTS FROM COAL WHICHCOMPRISES: (A) PREPARING A SLURRY OF FINELY DIVIDED COAL PARTICLES IN AHYDROGENATED AROMATIC HYDROGEN-DONOR SOLVENT HAVING A BOILING POINT INTHE RANGE BETWEEN ABOUT 350*F. AND ABOUT 800*F. IN A SLURRY PREPARATIONZONE; (B) INTRODUCING SAID SLURRY FROM SAID SLURRY PREPARATION ZONE INTOA FLUIDIZED BED COKING UNIT REACTION ZONE; (C) WITHDRAWING OVERHEADPRODUCTS FROM SAID FLUIDIZED BED COKING UNIT REACTION ZONE ANDRECOVERING AN INTERMEDIATE FRACTION BOILING IN THE RANGE BETWEEN ABOUT350*F. AND ABOUT 800*F. (D) HYDROGENATING SAID INTERMEDIATE FRACTION ANDINTRODUCING AT LEAST PART OF THE HYDROGENATED PRODUCT INTO SAID SLURRYPREPARATION ZONE; (E) TRANSFERRING SOLIDS FROM SAID FLUIDIZED BED COKINGUNIT TO A BURNER AND BURNING A PORTION OF THE SOLIDS TO PROVIDE HEAT FORTHE PROCESSL AND (F) RECYCLING HOT SOLIDS FROM SAID BURNER TO SAIDFLUIDIZED BED COKING UNIT REACTION ZONE.